Refrigeration



y 2, 1940- A. LENNING REFRIGERATION Filed Sept. 14, 1936 3 Sheets-Sheet 1 2 INVENTOR.

M ATTORNEY.

July 2, 1940. 2,206,411

A. LENNlNG REFRIGERATION Filed Sept. 14, 1936 3 Shoots-Sheet 2 65 65' ,5 w 7M 4. ,6? 6739 W VENIOR.

9/ BY Q/ WM ATTORNE July 2, 1940; 2,206,411

A. LENNING REFRIGERATION Filed Sept. 14, 1936 3 Sheets-Shoat 3 7/ I \fl'll I W n t /0 .20 E 1%VENTQR. l /W0 1 BY 1w ATTORNEY.

Patented July 2, 1940 UNITED STATES PATENT orrics REFRIGERATION Application September 14, 1936, Serial No. 100,613 In Germany November 21, 1935 19 Claims.

My invention relates to refrigeration, and more particularly to control of refrigeration apparatus. It is an object of my invention to provide an improved control device for modifying the normal operation of refrigeration apparatus, such as to initiate defrosting thereof or to instigate quick freezing, the device being operative to terminate the modified operation of the apparatus automatically.

Further objects and advantages of my invention will become apparent from the following description and accompanying drawings forming a part of this specification, and of which Fig. 1 diagrammatically illustrates refrigeration apparatus provided with a control device embodying my invention; Fig. 2 is an enlarged vertical sectional view of the control device shown in Fig. 1 taken on line 22 of Fig. 3; Fig. 3 is a sectional view taken on line 33 of Fig. 2 illustrating more clearly parts of the control device; Fig. 4 is a fragmentary sectional view taken on line 4-4 of Fig. 2; and Fig. 5 is a vertical sectional view of a modification of the control device shown in Fig. 2.

23 Referring to Fig. l, I have shown my invention in connection with a refrigerator cabinet Ii], only a part of which is' illustrated, having thermally insulated walls II defining a storage compartment I2. A door (not shown) may be hinged to the front of the cabinet whereby access may be had into the storage compartment I2. A cooling element Id of refrigeration apparatus is arranged within the storage compartment i2 for maintaining the latter at a desired low temperature. The refrigeration apparatus I have shown is of a uniform pressure absorption type which is well known in the art and in which an auxiliary pressure equalizing gas is employed.

It is to be understood, however, that my invention can be employedwith other types of refrigeration apparatus.

The refrigeration apparatus includes a generator l5 containing a refrigerant in solution in an absorption liquid, and, although I do notwish to be limited thereto, the refrigerant may be ammonia and the absorption liquid may be water. The generator I5 is provided with an upward extending pocket l6 Within which is arranged an electrical heating element H.

m The heat applied to the generator I5 and its contents expels the ammonia out of solution, and the ammonia vapor flows upward to an aircooled rectifier l8 which condenses any water vapor accompanying the ammonia vapor. The water condensed in the rectifier drains back to the generator, and the ammonia vapor flows upward to an air-cooled condenser [9.

The ammonia is liquefied in the condenser l9 and flows through a conduit 20 into the upper end of an evaporator coil 2| which is arranged closely adjacent to a shell and with the latter forms the cooling element H. An inert gas, such as hydrogen, enters the upper end of the evaporator coil 2| from a vertically extending conduit 22. The hydrogen and ammonia flow in the same direction in the presence of each other, and the ammonia evaporates and diffuses into the hydrogen with consequent absorption of heat from the surroundings of the cooling element. The resulting gas mixture of ammonia and hydrogen flows from the evaporator coil 2| through the outer passage 23 of a gas heat exchanger 24 and conduit 25 which communicates at its lower end with the lower .end of an absorber 26 about which is arranged a coil 21 through which a cooling medium may be circulated. If desired, the absorber 26 may also be air-cooled in a manner similar to the condenser i9.

In the absorber 26 the ammonia is absorbed out of the gas mixture into weak absorption liquid which enters the upper part of the absorber through a vertically extending conduit 28. The hydrogen, which is practically insoluble and weak in ammonia, passes upward from the absorber 26 through conduit 29, a plurality of parallel tubes 30 which form the inner passage of the gas heat exchanger 24, and conduit 22 to the upper end of the evaporator coil ii. The gas heat exchanger 24 transfers heat from gas weak in ammonia which is flowing to the evaporator coil 2| to gas rich in ammonia which is flowing to the absorber 26. A conduit 20a. extending upward from the lower end of the condenser l9 and thence downward and communicating with the outer passage 23 of the gas heat exchanger 24 is providedso that any ammonia which is not liquefied or hydrogen can flow to the gas circuit and not be trapped in the condenser.

The absorption liquid flowing downward through the absorber 26 incounterfiow. to the gas mixture becomes enriched in ammonia. by absorption and flows through an inner conduit 3| of a liquid heat exchanger 32 to a coil 33 disposed about the lower end of the pocket I8.

The rich absorption liquid is raised by vapor-lift action from the coil 33 through conduit 34 into the upper part of the generator IS. The absorption liquid is raised to a higher level in the generator l5 than it is in the absorber 26, and absorption liquid weak in ammonia flows from the lower part of the generator through conduit 35, outer conduit 36 of the liquid heat exchanger 32 and conduit 28 into the upper part of the absorber 26.

In accordance with my invention the electrical heating element H, which serves as a source of energy for the refrigeration apparatus, is controlled by. a device 31 provided with a switch which is connected in series relation with the heating element to a source of electrical supply indicated at 38. Referring to Figs. 2 and 3, the device 31 includes a two-part casing 39 having an upwardly extending boss 48 in the right hand part thereof to which is secured a base plate 4| of a mercoid switch having a removable cover 42. The mercoid switch comprises a bulb 43 containing a body of mercury 44 and having two spaced depending parts to the lower ends of which are fixed conductors 45 and 46 which are connected to terminals 41 and 48 mounted on the base plate 4|. The base plate 4| is provided with an opening 4|a through which pass the conductors of the electrical circuit which are connected to the terminals 41 and 48.

The bulb 43 is mounted on a member 49 having bent ends 58 which are secured to an inverted U-shaped member The member 5| is provided with openings in the side walls thereof which receive a pin 52 fixed to spaced vertical brackets 53 which are mounted on the base plate 4|. The inverted U-shaped member 5| and bulb 53 carried thereby rock about the pin 52, and one of the brackets 53 is provided with inwardly extending projections 54 and 55 which limit the extent of rocking movement of the member 5| and bulb 43. When the right hand part of the bulb 43 is tilted downward in the position shown in Fig. 2, with the member 5| bearing against the right hand projection 55, the body of mercury 44 does not provide an electrically conductive path between the conductors 45 and 46, whereby the electrical circuit is open and the heating element I1 is disconnected from the source of supply 38. When the left hand part of the bulb 43 is tilted downward with the member 5| bearing against the left hand projection 54, the body of mercury 44 provides an electrically conductive path between the conductors 45 and 46, whereby the electrical circuit is completed and the heating element I1 is connected to the source of supply 38.

In order to rock the bulb 43 about the pin 52 to connect and disconnect the heating element H to and from the source of supply 38, a pin 56 is secured to the side walls of the inverted U- in two inwardly extending projections formed in the right hand part of the casing 39. By moving the lever 58 about the pin 68 the inverted U-shaped member 5| is caused, by means of the bifurcated arms 51 and pin 5'6, to rock about the pin 52 and move the bulb 43 to open or close the electrical circuit, as described above.

The mechanism for controlling the lever 58 and hence the position of the bulb 43 includes a short rod 6| having a rounded end 62 which fits into openings formed in the spaced walls at the lower end of the lever 58. To maintain the rounded end 62 of the rod 6| between the spaced walls at the openings formed therein the bent portion of the lever 58 and the main body portion thereof are maintained in fixed spaced relation by a screw 63, as shown in Fig. 3.

The rod 6| extends through an annular member 64 into a housing 65 within which is threadedly secured a sleeve 66 havinga shoulder adapted to bear against a flange formed on the annular member 64. The housing '65 is closed at one end and provided with a flange at its other end to which is secured one end of an expansible bellows 61. The opposite end of the expansible bellows 61 is secured to a raised portion of a plate 68. a

To transmit axial movements of the bellows 61 to the rod 6| and also provide fora certain amount of play in the mechanism so that parts of the switch are not unduly strained, helical springs 69 and 18 are arranged within the housing 65. The helical spring 69 is disposed about the rod 6| with the ends thereof bearing against a flange provided at one end of the rod and the flange formed on the annular member 64. The helical spring 18 is larger than the spring 69 and the ends thereof bear against the flange formed on the annular member 64 and the closed end of the housing 65. The springs 69 and 18 form a resilient connection between the rod 6| and bellows 61 whereby axial movements of the latter are effectively transmitted to the rod 6| and whereby any excessive movement of the bellows that may take place in either direction is taken up by the springs 69 and 18 after the inverted U-shaped member 5| has contacted the stops or projections 54 and 55.

The plate 68 is provided with a threaded stud 1| which extends through an opening in the end of the casing 39. An internally threaded nut 12, which is rotatable and axially immovable, is positioned at the opening at the end of the casing and receives the threaded stud 1|.

The nut 12 is provided with a flange 13 which bears against the inner surface of the end wall of the casing, and to the portion thereof extending outside the casing is secured, as by set screws 15 and 16, a control knob 14 which bears against the outer surface of the end wall of the casing. To prevent any rotation of the plate 68 and bellows 61 when ,axial movement is imparted thereto by turning the control knob 14, the casing 39 is provided with a groove 11 which is adapted to receive a downward extending projection 18 formed on the plate 68, as shown most clearly in Fig.4. The plate '68 is provided with a central opening 19 which communicates with a passage formed in the stud 1| to which is connected one end of a tube 88, the other end 7 of which is connected to a bulb 8| shown in thermal contact with the cooling element I4. Instead of arranging the bulb 8| in thermal contact with the cooling element l4, it may be arranged in any suitable manner to be responsive to a temperature condition affected by the cooling element l4. The chamber 82 defined by the housing and bellows 61, opening 19, tube 88, and bulb 8| constitute what is termed an expansible fluid thermostat which is filled with a suitable volatile fluid which increases and decreases in volume with corresponding changes in temperature.

When the cooling element |4 tends to rise above a desired low temperature the volatile flu d ncreases in volume and causes the bellows which is 81 to expand whereby the rod 6|, through the resilient connection effected by the springs 69 and 18, is moved toward the chamber 59. Such axial movement of the rod 6| moves the lever 58 about the pin 68 and rocks the member 5| and bulb 43 carried thereby from the circuit open position shown in Fig. 2 to a circuit closing position wherein the left hand part of the bulb 43 is tilted downward. With the mcrcoid switch in a circuit closing position, the electrical heating element is connected to the source of supply 38 whereby the generator I5 is effectively heated and cold is produced in the storage compartment H! by the cooling element l4 to maintain the latter at the desired temperature.

When the cooling element |4 tends to fall below the desired low temperature, the volatile fluid in the expansible fluid thermostat becomes reduced in volume, whereby the bellows 61 contracts to cause the rod 6| to move toward the plate 68. With such axial movement of the rod 6| the bulb 43 is moved from its circuit closing position to the circuit open position shown in Fig. 2, whereby the electrical heating element H is disconnected from the source of supply 38 and the production of cold in the storage compartment I2 is stopped to maintain the latter at the desired temperature.

The arrangement of the mechanism just described is such that with a slight movement of the rod 6| either to the left or right, a correspondingly greater movement of the lever 58 is effected at the bifurcated arms 51 to move the member 5| and bulb 43 to a position either to open or complete the electrical circuit of the heating element ll. By adjusting the initial position of the control knob 14 and bellows 61 which is bodily movable, the thermostatic control will normally be effective to maintain the storage compartment l2 substantially at a desired low temperature within a normal range of variations. Referring to Fig. 1, this may be accomplished by providing a plate 82 at the side of the casing 39 with the plate having a part 83 projecting forward which is in the path of movement of the upper set screw 16. The position of the set screw 16 relative to the part 83, such as the vertical position shown, for example, may be arbitrarily chosen as the position which will maintain the storage compartment l2 substantially at the desired temperature within a normal range of variations.

In many instances it is desirable to modify the above described normal operation of the refrigeration apparatus, and this is particularly true when it is desired to melt frost that has accumulated on the cooling element. In order that the device 31 shall be capable of modifying the normal operation of the refrigeration apparatus to permit defrosting of the cooling element I4. I provide a sleeve 84 which is arranged within the casing 39 and secured to the flange formed on the housing 65. The sleeve 84 is disposed about the bellows 61 and provided with pins or elements 85 and 88 which extend therefrom at diametrically opposite points through slots 81 and 88, respectively, which are formed at the top and bottom of the casing 39. About the casing 39 adjacent to the pins 85 and 86 is secured, as by set screws 89 and 90, an annular permanent magnet or an abutment 9| having afiinity in contact with the pins or elements 85 and 86 and separable hy a given force, value.

When it is desired to modify the normal operation of the refrigeration apparatus and permit melting of frost on the cooling element l4, the control knob 14 that is employed to regulate and vary the normal operation is moved from the position to which it is normally adjusted to a defrost position whereby the bellows 61, sleeve 84, and pins or elements 85 and 86 are moved in a direction away from the chamber 59 and the pins or elements 85 and 86 are attracted and held by the magnet or abutment 9| With the control knob 14 in the defrost position the bulb 43 is in the circuit open position shown in Fig. 2 and the electrical heating element I1 is disconnected from the source of supply 38. After the control knob 14 has been moved to the defrost position to initiate defrosting of the cooling element it may be immediately returned back to its original position which determines the low temperature at which the cooling element I4 is normally maintained. However, with such return movement of the control knob 14 toits original position, the pins or arma- V ture elements 85 and 86 and magnet 9| have affinity in contact and will remain attracted by the magnet 9|.

Although the pins or elements 85 and 88 remain attracted and held by the abutment or magnet 9|, these elements remain in actuatable relation to other parts of the mechanism. During this time the bellows 61 will not be effective to move the bulb 43 to its circuit closing position with a normal increase of the temperature of the cooling element I4 in the normal range of temperature variations. As the temperature of the cooling element |4 increases, the volatile fluid in the expansible fluid thermostat increases in volume. When the cooling element l4 reaches an abnormally high temperature beyond the normal temperature range, which temperature is preferably above the freezing temperature of water, the pressure of the volatile fluid in the chamber 82 is sufliciently great to overcome added resistance to movement caused by the abutment or magnet 9| and force the pins 85 and 86 away from the magnet 9| to separate the abutting parts. This permits the rod 6| to move toward the chamber 59 to cause the bulb 43 to move to its circuit closing position and connect the heating element I! to the source of supply 38 to restore normal operation.

During the period of time the bulb 43 is in its circuit open position and the heating element I1 is disconnected from the source of supply 38, the temperature of the cooling element l4 increases to a value above the freezing temperature of water and frost that may have accumulated on the cooling element M will melt and can be collected in a suitable receptacle (not shown). The control mechanism is preferably adjusted so that, when the control knob 14 is moved to initiate defrosting of the cooling element M, the latter will remain at a temperature above the freezing temperature of water sufliciently long to insure substantially complete melting of frost which has accumulated on the cooling element l4. The sleeve 84 and pins 85 and 86 are preferably formed of soft iron, and the magnet 9| is of adequate strength so that its attractive force will be compatible with that exerted by the bellows 61.

When the pins 85 and 86 are moved away from the magnet 9|, the bulb 43 is immediately moved to its circuit closing position to permit heating of the generator l5 so that the temperature of the cooling element l4 decreases to a value in the normal range of temperature variations. This normal range of temperature variations is determined, of course, by the position to which the control knob I4 has been returned after being moved momentarily to the defrost position to initiate defrosting.

After the cooling element I4 reaches the desired temperature at which it is adjusted to operate, the control device 31 will be effective to operate the merooid switch in response to temperature-changes of the cooling element I4 to maintain the latter substantially at the desired temperature in the normal range of temperature variations. During normal operation the magnet or abutment is out of reach of the pins or elements 85 and 86 which move within limitation for the normal temperature control. When frost has again accumulated on the cooling element I4 to such an extent that defrosting is desired, the control knob I4 is moved to its defrost position and then returned to its original position at which it is desired that normal operation will resume after the defrosting has automatically terminated.

In certain instances, particularly when it is desired to hasten the production of ice cubes in the cooling element, it is desirable to modify the operation of the refrigeration apparatus to maintain the cooling element I4 at an abnormally low temperature. In the present invention this is accomplished by providing the sleeve 84 with two additional pins or elements 92 and 93 which also extend through the slots 81 and 88, respectively, at the top and bottom of the casing. When it is desired to modify the normal operation of the refrigeration apparatus to maintain the cooling element I4 at an abnormally low temperature the control knob I4 is moved to a quick freezing position whereby the bellows 61 and sleeve 84 are moved toward the chamber 59 and the pins 92 and 93 are attracted and held by'the magnet 9|. After the control knob I4 has been moved to the quick freezing position, it may be immediately returned to its original position which determines the low temperature at which the cooling element I4 is normally maintained. With such return movement of the control knob." to its original position, however, the pins 92 and 93 having aflinity in contact with the magnet 9| remain attracted by the magnet 3|, and the bellows 6'! assumes such a position that the bulb 43 remains in its circuit closing position. With the pins 92 and 93 held by the magnet 9|, the bellows 61 will not be effective to move the bulb 43 to its circuit open position with a normal decrease of the temperature of the cooling element I4. As the temperature of the cooling element l4 decreases, the volatile fluid in the expansible fluid thermostat becomes reduced in volume. When the cooling element I4 reaches an abnormally low temperature, which temperature is preferably below the freezing temperature of water, the contracting force of the expansible bellows 61 becomes sufficiently great to overcome added resistance to movement caused by the abutment or magnet 9| and force the pins 92 and 93 away from the magnet 9I to cause the bulb 43 to move to its circuit open position and disconnect the heating element II from the source of supply 38.

During the period of time the pins 92 and 93 are attracted and held by the magnet 9|, the bulb 43 remains in its circuit closed position, thereby permitting the temperature of the cooling element I4 to decrease. In this instance the control mechanism is preferably adjusted so that, when the control knob I4 is moved to instigate quick freezing, the cooling element will reach a temperature below the freezing temperature of water to insure complete freezing of water in trays which have been placed in the cooling element.

When the pins 92 and 93 are moved away from the magnet 9| by the force of the bellows 61 due to contraction thereof, as described above, the bulb 43 is immediately moved to its circuit open position to disconnect the heating element II from the source of supply 38 so that the temperature of the cooling element I4 will increase to a value in the normal range of temperature variations. This normal range of temperature variations is determined by the position to which the control knob I4 has been returned after being momentarily moved to instigate quick freezing. After the cooling element I4 reaches the normal operating temperature, the device 31 will be operative to control the merooid switch in response to temperature changes of the cooling element I4 to maintain the-latter substantially at the desired temperature in the normal range of temperature variations.

In Fig. 5 I have shown a modification of my invention which is similar to the embodiment just described and differs therefrom in that the control device 31' is arranged to control the flow of gas to a burner 94. The burner 94 is arranged to project its flame into the lower end of a flue 95 which extends upward through the generator I5 and about which a vapor-lift coil 33', similar to the vapor-lift coil 33 in Fig. 1, is arranged.

A suitable combustible gas is delivered from a source of supply through conduit 98, control device 3'I', and conduit 91 to the burner 94. A bypass conduit 98 is provided around the control device 31' to maintain a pilot flame at the burner 94 when the supply of gas to the latter is shut off.

The control device 31' comprises a two-part casing 39' having bosses 99 and I in the right hand part thereof which form inlet and outlet openings, respectively, for the combustible gas. The gas flows from the inlet opening at the boss 99 into diaphragm chamber 59, and from the latter through a port |0| into a valve chamber I02 which communicates with the outlet in the boss I00.

The port IOI forms a valve seat which is adapted to cooperate with a valve I03 having a hollow,

stem I04. Between a shoulder formed on the stem I04 and a short sleeve I05 threadedly secured to the stem is fixed a resilient diaphragm I06. The peripheral edge of the diaphragm I03 is secured between a shoulder formed on the inside of the casing 39' and a plate I01 having an opening through which the sleeve I05 extends and in which it is guided. The resilient diaphragm I06 is provided to make diaphragm chamber 59' gas-tight so that the flow of gas from this chamber to the outlet opening at the boss I00 is insured.

The valve I03 is urged or biased toward its closed or seated position by a helical spring I08 disposed within the valve chamber I 02. The valve I03 is urged to its open position against the tension of the spring I08 by means including a rod 6| which extends into the hollow stem I02. The rod BI is enlarged at one end and threadedly secured within a housing 65. The housing 65 and other parts of the control device 31' are similar to the control device 3'! described above and are referred to by similar reference numerals, so that a description thereof above the desired temperature the expansible fluid thermostat causes the bellows 6'! to expand and move the valve I03 to the right against the tension of the helical spring I08 to increase the flow of gas to the burner 94; and conversely,

I when the cooling element I4 tends to fall below the desired temperature, the expansible fluid thermostat permits the bellows 61 to contract and allowthe valve I03 to be urged toward its closed position to decrease the flow of gas to the burner 94. By adjusting the initial position of the control knob I4 and hence the position of the bellows 61, the thermostatic control will normally be effective to maintain the storage compartment I2 substantially at a desired temperature in a normal range of temperature variations.

the control knob 14 is momentarily moved to the defrost position and subsequently moved back to its original position, the bellows 61 and rod 6| will not be effective to open the valve I03 volume.

with a normal increase of the temperature of the cooling element I4. As the temperature of the cooling element I4 increases the volatile fluid in the expansible fluid thermostat increases in When the cooling element I4 reaches an abnormally high temperature beyond the normal temperature range, which temperature preferably is above the freezing temperature of water, the pressure of the volatile fluid in the chamber 82 is sufiiciently great to overcome added resistance 'to movement caused by the abutment or magnet SI and force the pins 85 and 86 away from the magnet 9|, whereby the rod BI is moved toward the right so as to con- -tact valve I03 and open the latter.

During the period of time the bellows 61 is contracted and the rod BI does not positively control the valve I03, the supply of gas to the burner 94 is reduced, thereby decreasing the heating of the generator I5 and permitting the temperature of the cooling element I4 to increase. When the temperature of the cooling element I4 increases to a value above the freezing temperature of water, frost that may have accumulated on the cooling element I4 will melt and can be collected in any suitable manner.

When the pins 85 and 86 are moved away from the magnet 9|, as described above, the valve I03 is immediately moved to an open position to permit heating of the generator I5" so that the temperature of the cooling element I4 will decrease to a value in the normal operating range of the apparatus.

When it is desired to maintain the cooling element I4 at an abnormally low temperature the control knob I4 is momentarily moved to the quick freezing position and subsequently returned to its original position which determines the low temperature at which the cooling element I4 is normally maintained. With such return movement of the control knob 14 to its original position, however, the pins 82 and 93 remain attracted by the magnet SI and the bellows 6'! assumes such a position that the rod GI maintains the valve I 08 open against the tension of the spring I08. With the pins 82 and 93held' by the magnet 9| the bellows 61 will not be effective to move the rod 6I'- toward the left and permit the valve I03to' move toward its closed position with a normal decrease of the temperature of the cooling element I4. As the temperature of the cooling element I4 decreases the volatile fluid in the expansible fluid thermostat becomes reduced in volume. When the cooling element I4 reaches an abnormally low temperature beyond the normal temperature range, which temperature is preferably below the freezing temperature of water, the contracting force of the bellows 61 becomes sufliciently great to overcome added resistance to movement caused by the abutment or magnet 9| and force the pins 92 and 93 away from the magnet 9|, whereby the rod 6| is moved toward the left to permit the valve I03 to move to its closed position due to the tension of the spring I08.

During the period of time the pins 92 and 93 are held by the magnet 9| and the bellows 61 does not positively control the valve I03, the

supply of gas to the burner 94 is increased,

thereby increasing the heating of the generator I5 and permitting the temperature of the cooling element I4 to decrease. When the temperature of the cooling element I4 decreases to a value below the freezing temperature of water, the water is completely frozen.

When the pins 92 and 93 are moved away from the magnet 9| by the contracting force of the bellows 61, as described above, the rod BI is moved toward the left and the valve I03 is immediately moved toward its closed position to reduce the supply ofgas to the burner 94 so that the temperature of the cooling element I4 will increase to a value in the normal range of temperature variations. This normal range of temperature variations is determined,'as mentioned above, by the position to which the control knob I4 is moved after being moved momentarily to initiate quick freezing.

In view of the foregoing it will be understood that I have provided an improved control device for refrigeration apparatus which is operative either to initiate defrosting or instigate quick freezing, the device being automatically operative to terminate such defrosting or quick freezing. Although I have shown several embodiments of my improved control device in connection with a particular type of refrigeration apparatus, I do not wish to be limited to the particular arrangements set forth, and I intend in the following claims to cover all modifications which do not depart from the spirit and scope of my invention.

What is claimed is:

1. In refrigeration apparatus including a cooling element, a source of energy for said apparatus, control means including a part normally responsive to a temperature condition affected by said cooling element to control said source of energy, a magnet, an armature element carried by said part, said magnet and armature element normally being spaced apart, and means for causing said armature element to be attracted and held by said magnet to modify the control of said source of energy and permit said cooling element to reach an abnormal value of temperature, said control means being automatically operative when said cooling element reaches an abnormal value of temperature to force said arma ture element away from said magnet so that said control means is operative to resume the normal control of said source of energy.

2. In refrigeration apparatus including a cooling element, a source of energy for said apparatus, control means including a thermal element normally responsive to a temperature condition affected by said cooling element for controlling said source of energy, a magnet, an armature element carried by said thermal element, said magnet and said armature element normally being spaced apart, and means for bodily moving said thermal element to cause said armature to be attracted and held by said magnet to modify the control of said source of energy and permit said cooling element to increase to an abnormally high temperature, said thermal element being capable of expanding when said cooling element increases to an abnormally high temperature to force said armature element away from said magnet so that said control means is operative to resume the normal control of said source of energy.

3. In refrigeration apparatus including a cooling element, a source of energy for said apparatus, control means including a thermal element normally responsive to a temperature condition affected by said cooling element for controlling said source of energy, a magnet, an armature element carried by said thermal element, said magnet and said armature element normally being spaced apart, and means for bodily moving said thermal element to cause said armature element to be attractedand held by said magnet to modify the normal control of said source of energy and permit said cooling element to decrease to an abnormally low temperature, said thermal element being capable of contracting when said cooling element reaches an abnormally low temperature to force said armature element away from said magnet so that said control means is operative to resume the normal control of said source of energy.

4. In refrigeration apparatus, a control member, a thermal element to normally operate said control member, means including a part manually movable to adjust the operation of said control member effected by said thermal element, a magnet, and an armature normally spaced from said magnet and movable with said thermal element, and means including said part to cause said armature to be attracted and held by said magnet to modify the normal operation of said control member.

5. In refrigeration apparatus, a control member, a thermal element to normally operate said control member, a magnet, and an armature normally spaced from said magnet and movable with said thermal element, and means to cause said armature to be attracted and held by said magnet to modify the normal operation of said control member by said thermal element, said thermal element being automatically operative upon a predetermined change of temperature to force said armature away from said magnet whereby said thermal element is operative to resume normal operation of said control member.

6. In a regulator for refrigeration apparatus including a control member and mechanism responsive to temperature of a body to be cooled within a normal range of variations to operate said control member, structure including an element movable responsive to such temperaturevariations .within limitation .for such normal temperature control, an abutment, and means to move said element into contact with saidabutment, said :abutmentbeing disposed out of reach of said element in normal operation, said abutment and element having aflinity in contact and separable by a given force value, said structure being so constructed and arranged that said element remains in actuatable relation to other parts of said mechanism when contacting said abutment, whereby temperature beyond normal range is effective to overcome added resistance to movement caused by such abutment and separate the abutting parts to restore normal operation upon predetermined variation of temperature from normal.

7. In a regulator for refrigeration apparatus including. a control member and mechanism responsive to temperature of a body to be cooled within a normalrange of variations to operate said control member, structure including an element movable responsive to such temperature variations within limitation for such normal temperature control, an abutment, and means to move said element into contact with said abutment, said abutment being disposed out of reach of said element in normal operation, said abutment and element being magnetically attractive to each other when in contact and separable by a given force value, said structure being so constructed and arranged that said element remains in actuatable relation to other parts of said mechanism when contacting said abutment, whereby temperature beyond normal range is effective to overcome added resistance to movement caused by such magnetic attraction and separate the abutting parts to restore normal operation upon predetermined variation of temperature from normal.

8. In refrigeration apparatus having a control element and mechanismfor normally operating the control element responsive to temperature in a normal range of variations, structure including a first member, a second member movable relative to said first member and normally out of reach of said first member during normal operation of the control element, said members being magnetically attractive, means to cause said second member to move toward said first member so that said members are magnetically held together, said members being separable by a given force value when magnetically held together, and said structure being so constructed and arranged that said second member is in actuatable relation to said mechanism when said members are magnetically held together, whereby temperature beyond normal range is effective to overcome added resistance to movement caused by the magnetic attraction of said members and separate said members to restore normal operation of the control element upon predetermined variation of temperature from normal. I

9. In refrigeration apparatus having a control element and mechanism for normally operating the control element responsive to temperature in a normal range of variations, structure including a first member, a second member movable with said mechanism, said second member being out of reach of said first member during normal operation of the control element, common means to adjust said mechanism to raise or lower the normal temperature range and to move said second member into abutting relation with said first member, said members having afiinity in contact and separable by a given force value, said structure being so constructed and arranged that said second member remains in actuatable relation to said mechanism when contacting said firstmember, whereby temperature beyond normal range is effective to overcome added resistance to movement caused by such abutment and separate said abutting members to restore normal operation of the control element upon predetermined variation of temperature from normal.

10. In refrigeration apparatus having a cooling element and mechanism responsive to a temperature condition affected by the cooling element for normally controlling the apparatus to keep the temperature condition in a normal range, structure including a first member, a second member movable with respect to said first member, said second member being out of reach of said first member during normal control of the apparatus by the mechanism, and means to cause said second member to bear against said first member, said members having aflinity to remain held together when said second member bears against said first member, and said structure being so constructed and arranged that said second member is operatively associated with the mechanism when bearing against said first member, whereby resistance to normal movement is effected to modify the control of the apparatus and cause an abnormal change in the temperature condition fromthe normal range.

11. In refrigeration apparatus having a cooling element and mechanism responsive to a temperature condition affected by the cooling element for normally controlling the apparatus to keep the temperature condition in a normal range, structure including two magnetically attractive members out of magnetic attraction during normal control of the apparatus by the mechanism, and means to cause one member to move toward another member so that said members are magnetically held together, said structure being so constructed and arranged that said one member is operatively associated with the mechanism when said members are magnetically held together, whereby resistance to normal movement is effected to modify the control of the apparatus and cause an abnormal change in the temperature condition from the normal range.

12. In refrigeration apparatus having a control device and mechanism including an expansible and contractible thermal element for normally operating the device responsive to temperature in a normal range of variations, structure including a first member movable with the thermal element, a second member out of reach of said first member during normal operation of the device by the mechanism, means to move said first member into contact with said second member, and said structure being so formed and constructed that said members have sufficient affinity when in contact to produce resistance to normal movement of the thermal element to modify the normal operation of the device by the mechanism and cause an abnormal change in temperature from the normal range.

13. In refrigeration apparatus having a control device and mechanism including an expansible and contractible thermal element for normally operating the device responsive to temperature in a normal range of variations, structure including two magnetically attractive members out of magnetic attraction during normal operation of the device by the mechanism, one of said members being operatively connected to the thermal element and movable therewith, means to cause the one member to move toward the other member so that said members are magnetically held together, and said structure being so constructed and arranged that said members when magnetically held together will produce resistance to normal movement of the thermal element to modify the normal operation of the device by the mechanism and cause an abnormal change in temperature from the normal range.

14. In refrigeration apparatus having a control device and means including an expansible and contractible thermal element for normally operating the control device responsive to temperature in a normal range of variations, said thermal element being bodily movable, structure including a first member movable with said thermal element, a second member normally out of reach of said first member, said members having affinity to remain held together when said first member bears against said second member and operative to modify the normal operation of the control device when bearing against each other, means to bodily move said thermal element to cause said first member to bear against said second member, and said structure being so constructed and arranged that said first member will be forced away from and out of reach of said second member to restore normal operation of the control device responsive to force produced by the thermal element upon variation of temperature beyond the normal range.

15. In refrigeration apparatus having a control device and means including an expansible and contractible thermal element for normally operating the control device responsive to temperature in a normal range of variations, said thermal element being bodily movable, structure including a first member movable with said thermal element and a second member normally out of reach of said first member, said members being magnetically attractive to each other and operative to modify the normal operation of the control device when said first member is moved toward said second member so that said members are magnetically held together due to the magnetic field therebetween, means to bodily move said thermal element to cause said members to be held together magnetically, and said structure being so constructed and arranged that said first member will be forced away from and out of reach of said second member to restore normal operation of the control device responsive to force produced by said thermal element upon variation of temperature beyond the normal range.

16. In refrigeration apparatus including a cooling element and control means for normally keeping the cooling element in a normal temperature range, structure including two magnetically attractive members normally spaced apart during normal control and operatively associated with the control means to determine an abnormal temperature beyond the normal range when caused to move toward each other so that said members are held together due to the magnetic field therebetween, and means to bring said members together so that they will be magnetically attracted to each other.

1'7. In refrigeration apparatus including a cooling element and control means for normally keeping the cooling element in a normal temperature range, structure including two magnetically attractive members normally spaced apart during normal control and operatively associated with the control means to determine an abnormal temperature beyond the normal range when caused to move toward each other so that said members are held together due to the magnetic field therebetween, and means including a single operating element for adjusting the control means to raise or lower the normal temperature range and for bringing said members together so that they will be magnetically attracted to each other.

18. In refrigeration apparatus provided with a cooling member and control means for normally keeping the cooling member in a normal temperature range, modifying means operatively associated with the control means for modifying the normal control whereby the cooling member is reduced to an abnormally low temperature below the normal temperature range, said modifying means normally being inoperative, and means including a single control member for adjusting the control means to raise or lower the normal temperature range and for rendering said modifying means operative to modify the normal control effected by said control means.

19. In refrigeration apparatus provided with a cooling member and thermostatic control means for normally keeping the cooling element in a normal temperature range, modifying means operatively associated with the thermostatic control means for modifying the normal control whereby the cooling element is reduced to an abnormally low temperature below the normal temperature range, said modifying means normally being inoperative, and means including a single control member for adjusting the thermostatic' control means to raise or lower the normal temperature range and for rendering said modifying means operative to modify the normal control, said thermostatic control means being operative when the cooling member reaches an abnormally low temperature to render said modifying means inoperativeso that normal control is effected by the thermostatic control means.

ALVAR LENNING. 

